Hydraulic actuators have been proposed generally to provide relative positioning of a load relative to a fixed reference. Such an actuator of the rotary vane type is disclosed in my U.S. Pat. No. 4,759,186. Also, such an actuator of the piston type is disclosed in my U.S. Pat. No. 4,753,071.
Conventional actuator systems require complicated and extensive peripheral equipment to produce sufficient power to control positioning. In applications where hydraulic power is utilized, the oil flow rate is relatively high, therefore requiring large valves, pumps and accumulator elements. In an application such as an aircraft where size and weight are critical, such constructions may be unacceptable. Moreover, the parasitic power required by such power actuator systems can reduce the overall system efficiency.
The present invention is intended to overcome these and other problems associated with actuator systems.